Wire and cable splices, preferred methods for use with automated processing systems
The definition of the preferred methods of splicing single core wires and multi-conductor cables supplied on reels by vendors to facilitate their automated processing on wire processing systems to allow continued uninterrupted machine operation without requiring operator intervention.
Rationale: At present electrical wire and cable for use in the production of aerospace and defense wire harnesses is typically supplied by manufacturers and distributors on reels. However, it is extremely difficult to manufacture the required lengths ordered by the end user as a single piece without any faults due to manufacturing limitations. It is therefore the norm to supply wire and cable as multiple segment lengths on the reel to make up the required overall length for an order. As a consequence the wire or cable is either left with the ends of each segment protruding from the side of the reel or the wire segments may be spliced together.
It is an aerospace industry requirement that splices should not pass through the manufacturing process and into the aircraft. To help ensure this does not happen it is typical to use a knot and splice detector on wire processing equipment, such as the laser wire markers used in the initial stages of harness preparation. This will automatically detect any splices and stop the wire processing machine. On an attended machine the operator can then check the fault and if it is a splice manually remove this and restart the machine. As more automated machines are introduced there is a need for splices to be not only automatically detected but automatically managed and rejected by the machine. This will require the splices to be of a size and form that can easily pass through the machine without operator intervention. In this way the machine can detect a splice, reject the wire in process and restart production to remanufacture the faulty wire and then continue in operation without the need for manual assistance. This feature is critical to automatic systems where there may not be an operator immediately to hand, and in particular for “lights out” operation on an unattended overnight shift.
At present some reels have wire segments that are not joined together, i.e. not spliced, meaning that at the end of a wire segment the machine would come to a halt, effectively having run out of wire despite the fact that there was wire remaining on the reel. Where wire is spliced there are no standards applied and no guidance on how to join the wire ends. Wire manufacturers and distributors therefore use a range of in house methods for splicing the wire they supply. This can often result in bulky splices which can be too large to pass freely through a typical wire processing machine. While an operator can manually remove the splice on an attended machine this becomes an impediment to automated wire processing machines. It is therefore necessary to define the methods and the physical forms for splicing wires to facilitate the automated processing of splices on an automatic wire processing machine, such that it can continue operation without the necessity of calling an operator to resolve the problem of a splice once detected. This ARP aims to set out acceptable means and forms of splices that will generally support the use of automated wire processing equipment.